From edd478269640b360c6f301f2baa04abdda563ef3 Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Wed, 22 Feb 2023 14:36:48 +0000 Subject: io_uring/rsrc: disallow multi-source reg buffers If two or more mappings go back to back to each other they can be passed into io_uring to be registered as a single registered buffer. That would even work if mappings came from different sources, e.g. it's possible to mix in this way anon pages and pages from shmem or hugetlb. That is not a problem but it'd rather be less prone if we forbid such mixing. Cc: Signed-off-by: Pavel Begunkov Signed-off-by: Jens Axboe --- io_uring/rsrc.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) (limited to 'io_uring') diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c index 4e6191904c9e..53845e496881 100644 --- a/io_uring/rsrc.c +++ b/io_uring/rsrc.c @@ -1162,14 +1162,17 @@ struct page **io_pin_pages(unsigned long ubuf, unsigned long len, int *npages) pret = pin_user_pages(ubuf, nr_pages, FOLL_WRITE | FOLL_LONGTERM, pages, vmas); if (pret == nr_pages) { + struct file *file = vmas[0]->vm_file; + /* don't support file backed memory */ for (i = 0; i < nr_pages; i++) { - struct vm_area_struct *vma = vmas[i]; - - if (vma_is_shmem(vma)) + if (vmas[i]->vm_file != file) { + ret = -EINVAL; + break; + } + if (!file) continue; - if (vma->vm_file && - !is_file_hugepages(vma->vm_file)) { + if (!vma_is_shmem(vmas[i]) && !is_file_hugepages(file)) { ret = -EOPNOTSUPP; break; } -- cgit v1.2.3-70-g09d2